This is the kind of tale that you don’t hear every day. Erik Wooldridge is a Systems Specialist at Morris Hospital near Chicago. During the installation of a new GE Healthcare MRI machine, he started getting calls that cell phones weren’t working. Then, some Apple Watches started glitching.

“My immediate thought was that the MRI must have emitted some sort of EMP, in which case we could be in a lot of trouble.” But an electromagnetic pulse would have taken out medical equipment in the facility as well, and they were working fine! He started investigating, and learned that every single impacted device was made by Apple—the technician’s Android phones were fine. And it was a wide-sweeping issue, impacting 40 different devices. What the heck?

I’ve seen a lot of strange glitches in my time, and I’ve never heard of something like this. Neither had Erik. “The behavior of the devices was pretty odd. Most of them were completely dead. I plugged them in to the wall and had no indication that the device was charging. The other devices that were powering on seemed to have issues with the cellular radio. The wifi connection was consistent and fast, but cellular was very hit or miss.”

That’s when he posted the issue to Reddit, where other sysadmins speculated that it might be caused by the liquid helium used to cool the MRI machine. So he investigated, and found there was a helium leak at the same time that vented into the building.

“I discovered that the helium leakage occurred while the new magnet was being ramped [down to cool it]. Approximately 120 liters of liquid [helium] were vented over the course of 5 hours. There was a vent in place that was functioning, but there must have been a leak. The MRI room is not on an isolated HVAC loop, so it shares air with most or all of the facility. We do not know how much of the 120 liters ended up going outdoors and how much ended up inside. Helium expands about 750 times when it expands from a liquid to a gas, so that’s a lot of helium (90,000 L of gaseous He).” I bet the nurse’s voices were higher pitched that day!

The devices started to slowly recover after the initial incident, but not completely. “We did have a few abnormal devices. One iPhone had severe service issues after the incident, and some of the [Apple Watches] remained on, but the touch screens weren’t working (even after several days.)”

He performed some triage, categorizing devices by type. “Models of iPhones and Apple Watches afflicted were iPhone 6 and higher, and Apple Watch Series 0 and higher. There was only one iPhone 5 in the building that we know of and it was not impacted in any way. The question at the time was: What occurred that would only cause Apple devices to stop working?”

This piqued my interest, and I reached out to some friends that make ‘MEMS’ silicon. These microelectromechanical systems are some of the smallest mechanical apparatuses in the world. Every phone has gyroscopes and accelerometers with micrometer-thin elements. My initial theory, shared by some on Reddit, was that the helium molecules were small enough to get inside these vacuum-sealed chips and interfere with the mechanical workings.

But there are two problems with this idea: One, Apple isn’t alone in using MEMS gyroscopes—every phone has them. Why weren’t the Android phones affected? Perhaps there’s a bug in iOS that causes crashes when it gets faulty data from the gyro? But the bug impacted Apple Watches, too—and they run WatchOS. Additionally, iPhones earlier than the 6 weren’t affected. It seems unlikely that this was a new software bug that impacted both iOS and WatchOS.

So what else could it be? Well, at the heart of every electronic device is a clock. Traditionally, these are quartz oscillators, crystals that vibrate at a specific predictable frequency—generally 32 kHz. When they were first invented, they enabled the first digital ‘quartz’ watches. Now, these frequency generators are at the heart of every electronic device.

Without a clock, the system stands still. The CPU flat out doesn’t work. The clock is literally the heartbeat of a modern device.

But quartz oscillators have some problems. They don’t keep time as well at high (and low) temperatures, and they’re a relatively large component—1×3 mm or so. In their quest for smaller and smaller hardware, Apple has recently started using MEMS timing oscillators from a specialized company called SiTime to replace quartz components.

A MEMS oscillator, as seen through an electron microscope.

Specifically, they’re using the SiT512, ‘the world’s smallest, lowest power 32 kHz oscillator.’ And if the MEMS device was susceptible to helium intrusion, that could be our culprit!

A failing oscillator would match Erik’s symptoms, which he reproduced in an experiment. “I placed an iPhone 8 Plus in a sealed bag and filled it with helium. This wasn’t incredibly realistic, as the original iPhones would have been exposed to a much lower concentration, but it still supports the idea that helium can disable the device. In the video I leave the display on and running a stopwatch for the duration of the test. Around 8 minutes and 20 seconds in the phone locks up. Nothing crazy really happens. The clock just stops, and nothing else. The display did stay on though.”

I was able to repeat his experiment in our lab. My iPhone 8 lasted about four minutes in a helium atmosphere before it shut off entirely.

Sure enough, Apple’s user guide for the iPhone and Apple watch admits this is a problem:

“Exposing iPhone to environments having high concentrations of industrial chemicals, including near evaporating liquified gasses such as helium, may damage or impair iPhone functionality. … If your device has been affected and shows signs of not powering on, the device can typically be recovered. Leave the unit unconnected from a charging cable and let it air out for approximately one week. The helium must fully dissipate from the device, and the device battery should fully discharge in the process. After a week, plug your device directly into a power adapter and let it charge for up to one hour. Then the device can be turned on again.” (Emphasis added.)

Hydrogen and helium are notoriously hard to contain because their molecules are so small. It sounds like this is a problem that SiTime has been working to solve for a while. I found this on their FAQ, “How effective is the hermetic seal of MEMS oscillators?”

“Previous generations of EpiSeal resonators may have been impacted by large concentrations of small-molecule gas. Newer EpiSeal resonators are impervious to all small-molecule gases. Please contact SiTime in case you are planning to use a SiTime device in large concentrations of small-molecule gas, so that we can recommend an appropriate, immune part.” (Emphasis added again.)

I was curious if this would impact other kinds of MEMS devices, so I reached out to InvenSense Motion, the company who makes the image stabilizing chip in the Pixel 3. David Almoslino, their Senior Director of Corporate Marketing, confirmed that it was an issue. He told me that their products “can be somewhat susceptible to helium. Helium can diffuse through the fusion bond oxide and cause the cavity pressure to increase. In our pressure sensors, helium could cause the absolute accuracy to temporarily degrade. In our gyro sensors, helium could cause the offset to drift and could cause the oscillation to temporarily stop. In any [accelerometer] sensors, helium should have very little impact. All our InvenSense parts should recover once removed from any helium environment.”

Of course, the reason that you’ve never heard of this before is because it’s such a rare situation. But silicon manufacturers are aware of it and do what they can to minimize the problem. David told me that “A helium leak test is a pretty standard MEMS test done by most companies to assess vacuum packages.”

So that’s it! Like an incredibly tiny grain of sand, the helium molecules are small enough to get inside the device, physically stop the clock, and turn your phone temporarily into a paperweight.

67 Comments on “iPhones are Allergic to Helium”

That GE Brightspeed imaged is in fact a CT scanner. Look at the length of the bore, the transparent middle ring where the x-ray tube rotates, also the lead apron on the patient protecting organs from stray radiation, additional clue should be the radioactive warning icon on one button.

>That GE Brightspeed imaged is in fact a CT scanner. Look at the length of the bore, the transparent middle ring where the x-ray tube rotates, also the lead apron on the patient protecting organs from stray radiation, additional clue should be the radioactive warning icon on one button.

Not to mention the patient is still wearing what appears to be metallic jewellery.

120L of liquid helium has a mass of only 15Kg. It will be be diluted to trace levels within a few minutes by normal air mixing. It will be completely removed by the airconditioning system within an hour.

Helium is very unlikely to diffuse into a phone at atmospheric pressure.

Little bit words for my iphone 8&X allergic: every 4 week my iphone was died (2 times per week i was visitted MRI techroom for service operations with different type and volume of Helium, gas or liquid, superclean or not, without magnetic field int the techroom of course)
at first: Model of MRI (Ge, Siemens, Toshiba and others) doesn’t matters
at second: quantity of helium in the space doesnt matter
hehe… now with S9+ no prob

We perform Fusion Cryoablation in the office setting, the freezing process requires argon gas and thawing helium. About a 18 months ago, out tech – who runs the machine- referred that his second iPhone 7 was down over the courae of 6 weeks. Inhot my iPhoneX November last year and a week later ‘died’ I performed 3 procedures that day. They ran all kind of tests at the apple store the next day and finally replaced. There was no explanation. The new one died two weeks later on a Friday and I was leaving town. Left the phone at home. The following Tuesday inhad an appointment at the apple store, however, that norning the iPhone came to life. Weeks later 5 different people had iphones dead, from iph6 to X. No android phone went down. I also saw my iwatch3 died. It came back to life buf dwfective. We secides to quarantine the iPhones out of the procedure room. No more events. Interestingly, it does not happen to iPads

Author stated that only 1 iPhone 5 was known to be in the facility and it was not impacted. From that author concluded that iphones prior to the 6 were unaffected. This is hardly a scientific conclusion…

Probably just stock medical instrument photos that somebody decided to drop into an article that referenced medical instruments.

I work in a cryogenic lab that uses liquid helium and we have several people with late-model iPhones and iWatches that have died. Initial suspicion, like in this article, was electrical or magnetic pulses. However, Health & Safety couldn’t find anything. This may explain both why E&S couldn’t find anything and why the Apple devices were dying.

It might be worth noting that “Sure enough, Apple’s user guide for the iPhone and Apple watch admits this is a problem:” appears to be a recent change. Try looking for this mention in past manuals (see FCC submissions, for example). I don’t think this particular incident is what led to the documentation change, but it does appear to be a very recent change.

This seems massively unlikely to me. The article other has buggered his units up. 120L of liquid goes to 90 cubic meters of helium gas. Over 5 hours. So either trace amounts of helium messes up iphones or the explanation is rubbish. I work with helium all the time, carelessly, and nobody in our building has had a dead phone.

As for how they might keep the helium out of the devices (MEMS):
Way back, one of my physics professors told us (students) about having helium leaking into a vacuum chamber he and some of his colleagues were using. It came to be that they determined that helium could penetrate the cast aluminum cover on the chamber. They changed the cover to one made of rolled aluminum and it solved the problem.

Not to say this couldn’t possibly happen, but I personally worked at the GE Healthcare Florence plant building and testing MRI scanners for 10 years. That place uses a crap ton of helium. There are magnets being ramped up and down and venting helium literally all day every day. That being said, there are plenty of employees working there that use apple products and I never saw anything happen like this article describes.

How does a small molecule (I read atom here since it is an element who’s molecule is just one atom) stay low enough in the atmosphere in such a high concentration that it would diffuse not only into a device but also into a tiny component within that device? Very curious situation to say the least however my biggest concern for Morris Hospital is the potential danger that could exist. Venting of He during the process of turning on a super conducting magnet, referred to as “Ramping” is normal and depending on the MRI’s vessel size quite normal for this amount of He to be burned off since the current required becomes rather high and some energy is lost in the process that creates a boiling off of the LHe. Since this is a known event and the possibility also exists that an unexpected failure of the magnet could occur, (Quench) these systems are designed ,(and required by the manufacturer) to have a He exhaust pipe with many safety considerations for prevention of that type of leak to be released inside a facility. I recommend that the manufacturer (GE Healthcare) be contacted immediately to ensure that a potentially deadly situation does not exist. If the magnet were to unexpectedly lose its super conducting ability there could be a boiling off of over a thousand liters of LHe and the resulting gas could displace normal atmosphere inside the building causing medical emergencies.
In the past 3 years we have installed 11 MRI’s here and that exhaust pipe is one of our primary safety concerns every time. Location, size of the pipe and consideration for other ventilation openings in our buildings all factor into this.
Erik, you should call 1-888-446-7484 to report this potential safety issue as soon as possible

Just to double check, I contacted a buddy of mine who still works at the GE MRI plant.
Me: At GE do people’s Apple products randomly die?
Him: Yes Iphone 8 or greater. They will eventually come back after a few days.

So there you go. That version was released in 2017 after I left that job, which is why I’d never seen it.

We recently ramped down and uninstalled a 3T GE Magnet. During the ramp down process, two iPhones stopped working. (One recovered after a week, the other never did.) According the the field service engineer who de-installs magnets for a living, this is a common problem. His entire crew has stopped using iPhones and switched to android phones which don’t have the problem. He attributed the problem to EMF noise caused by bleeding off current from the coils. That theory seems more probable than a low level He leak, but neither one seems likely.
I wonder if I could get a grant from Apple?

Setting aside what’s pictured in this article, to anyone who has says this is implausible, I work with MEMS sensors that are vacuum packaged and have seen the effects of relatively small concentrations of helium on our devices. The critical concept is that helium is free to move across the seal that blocks other gas, so over time the concentration of helium inside and outside the package will balance. There is normally very little helium in air, so releases of gas into a room will drive the concentration up by orders of magnitude even though the total percentage of the gas is still relatively low. That higher concentration diffuses into the MEMS package. MEMS oscillators require a vacuum to operate properly (https://en.m.wikipedia.org/wiki/Microelectromechanical_system_oscillator) so it isn’t surprising that corruption of the vacuum interferes with normal operation. Likely there is a small frequency shift with degraded vacuum, enough to disrupt the timing of the electronics that depend on stable clock frequencies. As for recovery, elevated temperature will help speed diffusion of helium back out of the package once the phone is in a normal atmosphere.

Most quartz oscillators aren’t running at 32kHz. You are getting confused by oscillators used in time-of-day clocks – like a wristwatch or a wall clock. Those oscillators typically run at 32kHz. No CPU oscillator runs that slow. Quartz CPU oscillator crystals typically run at tens to hundreds of MHz.

Thank you SO MUCH for your article. I work in an Magnetoencephalography lab (MEG for short) and over here we also use liquid helium to cool down our device. Exactly as this article mentioned we have had FIVE broken Apple watches and FIVE iPhones broken exactly 1 hour post helium fill. Apple watches were series 1 and 3 and the apple iPhones were all the iPhone 8.

It does seem to only effect these particular generations of devices: Series 1 and up for apple watches and iPhone 6 up (does not effect iPhone 6). Anything before these generations, and nothing happens to these older devices. Our lab has been pondering this mystery for the past 8 months and while we suspected it was the Helium we had no definitive way of confirming what was happening mechanically. When we use helium to cool down our machine, it goes from liquid to gas and we suspect it’s during this time our apple devices to malfunction. We reached out to Apple but they sort of dusted us off and gave us a generic response about the atmosphere etc, but nothing helpful aside from “avoiding explosive environments”.

Point is… folks get a different phone or enclose your apple devices if exposed to helium!!

This is known problem, – power supplies ramping up and down of MRI machines uses precisely the same frequancy/voltage as Apple wireless chargers. Only the currents generated are like 10000 times stronger.
Apple products suffer massive wireless charging overload even if the distance is like 5 meters from ramping power supply….

I can attest to this phenomenon, as I recently de-iced a magnet one evening, dumping a great amount of helium gas into the MRI’s site. The next morning the customer’s employees reported 11 iphones had failed. No Samsung’s reported dead.

Being an MRI engineer for over 25 years, I didn’t understand what happened. The MRI wasn’t even ramped up, and no scans were able to be performed.

I was of course blamed, as a matter of course (goes with the territory). I dismissed the matter as one of those things….

I can second that. Changing flux fields and gauss fields will interfere with the iPhones inductive charging. Many cases have been observed with the range of up to 30 meters away from the ramping. Most phones come back eventually after a long time of charging, but some never come back.

Concerning what Yoda, Tyler V., and Dr. Jones write, I agree that it is unlikely, that the main clock of the system is a 32.768khz oscillator. But if the oscillator is only used for the RTC, why does the phone totally depend on it working exactly?

The comments about 32768Hz oscillators not being used for system clocks (I.e RTC only) does not apply to a lot of modern electronics. High frequency crystals are often avoided to reduce radiated EMI. Both to meet regulatory requirements and to reduce the noise floor for any radio receivers located on the same board. Low frequencies are often multiplied by and on chip PLL or FLL to the desired higher clock frequency. Low speed clocks are sometimes used directly for CPUs in low power operation. Even when a CPU is in a high frequency clock domain derived from another source it oftrn needs to wait for a peripheral that may be in a low frequency clock domain that may be derived from a 32768Hz oscillator. If the peripherals clock stops completely then it may lock the CPU. So a great deal more than (real) time keeping can be affected.

@Technics
“High frequency crystals are often avoided to reduce radiated EMI. Both to meet regulatory requirements and to reduce the noise floor for any radio receivers located on the same board. Low frequencies are often multiplied by and on chip PLL or FLL to the desired higher clock frequency.”

Thanks a lot, now we are getting somewhere. Not that I want to deny what you are saying, but how exactly is this advantageous? As I understand it, you still have the high frequency somewhere, you still need to spreed it all over the core of the CPU, because every latch or thingy there needs to know at what exact state the rest of the system is, in order to work in sync with it.

“Even when a CPU is in a high frequency clock domain derived from another source it oftrn needs to wait for a peripheral that may be in a low frequency clock domain that may be derived from a 32768Hz oscillator. If the peripherals clock stops completely then it may lock the CPU.”

This goes along with the article which says “Why weren’t the Android phones affected? Perhaps there’s a bug in iOS that causes crashes when it gets faulty data from the gyro?”

I’d second that. That is, calling this an OS bug, if it is so. Seriously, a total system lockdown if some data form some sensor does not arrive as expected?

@thorstenv
Firstly. You will need a PLL anyway because you won’t get a crystal at the CPU frequency on a modern device. The advantage of a low speed crystal reference + on chip PLL over a high speed crystal is that the the high frequencies are contained to a small, tightly controlled area on a silicon die which limits the radiating “antenna” to a much short length than even the shortest PCB trace. You can also control the slew rate to limit harmonics. A crystal requires a certain amount of drive current that current needs flow through a PCB trace. The “out” pin of a crystal oscillator is going to have something fairly close to a square wave signal (hence lots of harmonics at much higher frequencies than the crystals fundamental). So there can and usually will be lots of radiated EMI at undesirable frequencies. It’s not just the oscillators where this is necessary for EMI and radio performance. Pretty much any high speed signal (say to the RAM) on a PCB is going to have some form of series termination to limit slew rates and harmonics (as well as ringing) in devices like these.

You can get MEMS oscillators with the PLL built in but the idea is that output is low voltage, low drive current and has a low slew rates to limit emissions.

As to Android phones. MEMS oscillators probably aren’t used. Apple will be using them because they are tiny. They also have a few other advantages and Apple can cover the higher cost with a combination of buying power and in the “Apple tax” their users are willing to pay. Most Android phones are probably still using standard 32768Hz tuning fork type crystals to do the same job. At the low 32768Hz frequency and with the tiny drive currents these crystals require any EMI they radiate is typically a non-issue.

20 years of fixing mri’s and I never experienced it. I’ve always had I Phones onsite.
One thing I CAN tell you is that the I Phone has the greatest resistance to high field magnets of all the phones. Im constantly crawling around the machines with the phone in my pocket, or using it to take close up pics of things. All while the magnet is on, or ramped up. Great phone.

For my job I’m often around NMR magnets which works the same like MRI but has a vertical bore.
So they also need liquid helium to cool the superconducting magnet. The LHe boils off and contaminate the air around.
We found out that very small amounts of gases is enough to shut down iPhone 8 and X for one to three days.
Older models like iPhone 6s and 7 do not shut down but have serious problems for a day or so with mobile network connections. Wifi is fine.
Model 6 and older does not get affected due to our experience.
I hope Apple will fix this problem with the next generation.

My boss had the exact same problem. His iPhone 8 failed, was repaired then the replacement failed during a helium fill of our nuclear magnetic resonance spectrometers… He got the cash back for the 0hine and bought an iPhone 6!

Working in inert atmosphere gloveboxes, it is well know that dry helium (and argon) knocks down static to zero while dry nitrogen atmospheres have static problems. Low levels of helium can alter charging in gas phase reactors as well. We never looked into why but suspected helium ionizes readily and facilitates movement of charge to neutralize static. If the micro devices have significant potential differences, perhaps helium is interfering.

Thank you for this article. This describes our problem exactly. We have a SQUID-based device that gets filled with liquid helium every week leading to slightly higher than normal concentration of helium in our building. For over one year, ever since I upgrade to the iPhone 7, I have been complaining to Apple that my phone was having problems after spending time in my building. At the same time a co-worker upgraded to an iPhone 8 and her phone would discharge after being in the building after some time. I spent several months and over 6 hours with Apple and AT&T (my carrier) trying to trouble shoot the issues. For months I was frustrated that I was not being able to use my phone except after being away from work for over 24 hours.
I conducted a series of experiments to reproducibly confirm that the source of the problem was being inside my building. It did not matter if my phone’s WiFi was off, in airplane mode or even powered off, my phone stopped connecting to the network and the eventually to WiFi networks after spending a few hours in my building. Also I knew that no other brands of phones and iPhones versions 6 and older were not affected. To Apple’s credit they gave me several different phones including deleting all my data saying my profile was corrupted. I continued to insist that the problem was their phone (my iPhone 5 had worked totally fine for years) and that giving me another was not going to fix the problem. In my final meeting with them the Smart Bar Employee chimed in and said “remember in a meeting Apple told us that starting with the 7 the technology changed and the new phones are more susceptible to ‘environmental’ problems?” At the manager washed her hands of the issue and said it was my work’s problem, but I rebutted and said that it may be something at my work but the new version of the phones were flawed. I tried to escalate the matter at Apple and their final solution was for me to purchase a upgraded phone. I am still frustrated since I cannot bring my phone to work! I started getting my work’s administration involved when some of our patients’ iPhone X and Apple watches stopped working after spending some time in our building. This causes a liability problem for our Hospital. We have been troubleshooting with Apple engineers for several months with no solution until now. I hope that Apple takes notice and fixes this problem. More people will be affected as they “upgrade” their phones. It sounds like Apple knew about this issue and they have not taken the proper steps to notify their consumers, nor properly train their own staff to resolve these issues. These phones are expensive! Cellular service is expensive! Apple consumers should expect these products to work. I am curious to see how Apple will handle this. As a side note, we have noticed that FitBits do not work in our building as well after long exposures. I am wondering if its a similar problem.

“A MEMS accelerometer under an electron microscope at 50 micrometer resolution.”
Of course the resolution of the EM image is much lower than 50 microns; In the sub-micron scale. The 50 micron on the bottom right is just as scale.

There are some technological error statements in the text and on the pictures captions. The clock frequency inside a regular iPhone or Android device is waaaaay over the 32kHz stated in the text, the Iphone processors run over 2GHz, while Android runs around half of that and it is frequency adjustable by the processing necessity. Also, without external gas pressure being greater than the internal pressure of the chips, gases will have a very long hard time to enter the chips. This may happen if the chips cools down rapidly reducing inner pressure, sucking some gaseous around the chip. Other than that, it will take many hours for one molecule of “regular air” gets out and being replaced by a molecule of “helium”. The machine shown at the picture is NOT an MRI, it is a CAT Scan (Computer Tomography), it uses several pictures of X-ray to create the 3D image. CT Scan does not need Helium to cool down anything, since it doesn’t use Super Conductor Coils to generate the humongous magnetic field required on the MRI machine. As usual, when a text starts to present different and several flaws, it looses technical credibility.

An MRI does not give off an EMP.
I suppose the pressure is plausible. Helium is used for leak detection because it is an atomic (vs hydrogen which is molecular here on Earth) so it has a smaller diameter than every other atom or molecule. I imagine that the device is sealed for atmosphere with is primarily molecular nitrogen and molecular hydrogen. Helium could have migrated in and increased the pressure but highly unlikely because the helium goes up even in turbulence. Even so, it would be one or two parts per million inside the watch which would not be sufficient to cause any problems. Helium has supreme thermal transfer properties but again, insufficient quantity. The liquid helium for cooling the relatively low magnetic flux of the MRI cools it directly and not by evaporation. I am guessing that the hospital just got a bad batch of the Chinese manufactured products.

Wagner Lip, if you refresh your knowledge of Partial Pressure, then perhaps you might want to rethink your statement “Also, without external gas pressure being greater than the internal pressure of the chips, gases will have a very long hard time to enter the chips.” Keep in mind also that helium atoms can sneak through tiny spaces that are too small for air molecules to penetrate. They are not likely to be slowed down by chemical reactions as they sneak through either, as helium is chemically inert. It takes a LOT of energy to ionise a Helium atom.
I wonder what kind of vacuum there is inside the MEMs devices ? It must be an extremely hard vacuum!

It is puzzling to me that the MEMs device could recover in normal atmospheric pressure if the device itself has a vacuum inside. What force would make the tiny Helium atoms migrate back out of the MEMs once they are comfortably inside wreaking havoc? You would need another vacuum outside to evict them from their new home.

Soo, what does the iPhone and the Apple Watch use the 32 kHz oscillator for? That’s surely not the CPU, those vibrate at 100s of MHz or GHz frequencies. Seems to me that would be sort of a very low-end auxiliary chip inside the phone, but surely that shouldn’t stop the CPU from working? Something is off here.

The 32,760 clock when divided by 546 is 60, as in seconds per minute. This time is very accurate short term but is updated by the GPS 1 PPS signal periodically. A critical requirement is for phones to stay time synced with the network, especially for GSM phones that share spectrum in time slots.

(32 kHz clocks were developed originally to keep TV color automatically time sync’d with the picture, as a result they are very high volume and low cost)

A MEMS clocks isn’t like a quartz crystal where a slab of quartz is sandwitched between two pizoelectice transducers. The crystal would be massively thick. Instead they use a micro weight on the end of a miniature spring (i.e. MEMS) that forms a resonate “pendulum” at the 32 kHz which imparts its motion into a pizoelectric material to convert its vibrations into a voltage waveform. Unfortunately being a “mechanical” device its frequency is dependent on the density of the atmosphere around it much like a guitar string or vocal cord. If the device is calibrated in one atmosphere such as a vacuum and that atmosphere is changed to He the frequency will no longer be calibrated.

My guess is Apple switched from a $1 part in a sealed glass/metal hermatic package to a $0.80 plastic part with a much higher leak rate……

Additionally those expanded 90 thousand liters of He sound much, but let there be a corridor (or a hall or a room) 3m wide and 3m high, then all of them would fit in 10m of that corridor. And that “huge” amount of gas evaporates slowly(!) over 5 hours in a proper air-conditioned and ventilated facility. All in all I would say: there was nearly no He at all that could leak in some 40 phones placed all around that facility.

Its strange to compare that climatic situation to that one in a plastic bag with pure He inside.

The problems reported here were caused by something else. As a electronic hardware designer I would blame that MRI device generating spurious EMP or causing unstable supply voltage to devices connected to AC-chargers.

“…Models of iPhones and Apple Watches afflicted were iPhone 6 and higher, and Apple Watch Series 0 and higher.”

Just a note that:
1. “Apple Watch Series 0” became an unofficial name for the “Apple Watch (1st generation)” after the subsequent “Apple Watch Series 1” and “Apple Watch Series 2” models were released a year later.
2. Apple Watch Series 0/(1st generation) is the oldest aka the “lowest” model of Apple Watch.